Effects of nutrients enrichment on algal communities: an experimental in mesocosms approach

Abstract

Aim:The effect of different concentrations of nutrients on algal communities living at the bottom of mesocosms was examined; Methods: The experiment was carried out in the tributary of Rosana reservoir (Corvo river) from November 22 nd to December 16 th of 2003. Mesocosms were set up in triplicate, with four treatments: nitrogen (N); phosphorus (P); nitrogen plus phosphorus (NP); plus a control treatment (C), consisting in addition of water from the reservoir; Results: Results of the Principal Components Analysis applied on the abiotic variables have shown that two axes explained 93.6% of the total variability (69.6 and 23.9%, respectively). It was possible to identify a group of P (positive) and N (negative) treatments of axis 1. The addition of nutrients in the experiment resulted in changes in algal composition. Mean values of density ranged from 8.383 to 34.510 ind.mL -1 . Higher densities occurred in the phosphorus and nitrogen plus phosphorus treatments. The most representative classes were Zygnemaphyceae, Chlorophyceae, Bacillariophyceae and Cyanobacteria, both in density and species richness; Conclusions: Phosphorus seems to be beneficial to green algae in general, since a marked increase in Zygnemaphyceae and Chlorophyceae was found in the treatments containing phosphorus and nitrogen plus phosphorus. In the nitrogen treatment, however, green algae decreased dramatically, while Cyanobacteria remained constant, indicating their capacity to live in changed environments and confirms the limiting role played by phosphorus on the algal groups.Keywords: benthic algal, phosphorus, nitrogen, Zygnemaphyceae, Chlorophyceae.Resumo: Objetivo: Este trabalho teve como objetivo avaliar a resposta das comunidades algais presente no sedimento de mesocosmos em diferentes concentrações de nutrientes; Métodos: O experimento foi realizado no afluente do reservatório de Rosana (rio do Corvo) no período de 22 de novembro a 16 de dezembro de 2003. Os mesocosmos foram preparados em triplicatas e em quatro tratamentos: (N) com adição de nitrogênio; (P) adição de fósforo; (NP) adição de nitrogênio + fósforo e o tratamento controle (C) com adição de água do reservatório; Resultados: Os resultados da Analise de Componentes Principais aplicados com dados abióticos mostram que os dois primeiros eixos explicaram 93,6% da variabilidade total dos dados (69,6 e 23,9%, respectivamente). Com isso foi possível identificar grupos de variáveis relacionadas ao tratamento com P (positivamente) e outro com nitrogênio (negativamente) no eixo 1. A adição dos nutrientes provocou alterações nos diferentes grupos de algas, com valores médios da densidade variando entre 8.383 to 34.510 ind.mL -1. Maior densidade foi observada no tratamento com P e NP, respectivamente. Zygnemaphyceae, Chlorophyceae, Bacillariophyceae e Cyanobacteria foram às classes mais representativas, tanto em densidade quanto em riqueza de espécies; Conclusões: O P parece beneficiar as algas verdes em geral, uma vez que no tratamento com P e com NP houve aumento acentuado...

Effects of the interaction between nutrient concentration and DIN:SRP ratio on geosmin production by freshwater biofilms

“…These results agree with recent studies describing how the phosphorus availability excess may stimulate the magnitude of cyanobacteria blooms (Jankowiak et al, 2019). Moreover, it has been described that certain cyanobacteria can store essential metabolic nutrients in the cytoplasm, especially under eutrophic conditions (Felisberto et al, 2011). For example, phosphorus can be accumulated in intracellular polyphosphate granules, whereas under nitrogen-limited conditions some cyanobacteria have also shown a high capacity to fix it (Felisberto et al, 2011).…”

“…Moreover, it has been described that certain cyanobacteria can store essential metabolic nutrients in the cytoplasm, especially under eutrophic conditions (Felisberto et al, 2011). For example, phosphorus can be accumulated in intracellular polyphosphate granules, whereas under nitrogen-limited conditions some cyanobacteria have also shown a high capacity to fix it (Felisberto et al, 2011). Different studies, performed mainly in lakes, have pointed out some nutrient thresholds to control the growth of cyanobacteria, such as the TP value, which had to be between 20 -100 µg TP/L (Li et al, 2018;Sharma et al, 2011).…”

Seasonal variations in response of periphytic algal community to nutrient enrichment in the river Ganga (Varanasi, India)

“…3À -P enrichment, thereby showing its liking for high nutrient concentration (Felisberto et al, 2011;Larson and Passy 2012). Incidentally, N. palea has been included in the list of algal species most tolerant to organic pollution (Palmer, 1969).…”

Ecotechnologies for Aquaculture Wastewater Treatment in a Water-Scarce Region

“…Monoraphidium contortum and Gomphonema sp. are present in effluents with high concentration of nutrients [66]. Epithemia adnata responds proportionally to the high nitrogenous nutrient supply and the increase in temperature [67].…”